Video content providing apparatus, control method thereof and system

ABSTRACT

A video content providing apparatus is provided, the video content apparatus including: an output portion comprising output circuitry configured to transmit a content signal for displaying an image to a relay connected to an image processing apparatus to provide the content signal to the image processing apparatus; and at least one processor configured to receive video formation information about a first video format supported by the image processing apparatus from among a plurality of video formats from the relay, and if it is determined that the relay does not support the first video format, to output the content signal corresponding to a second video format different from the first video format and supportable by the relay from among the plurality of video formats.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority under 35 U.S.C. § 119to Korean Patent Application No. 10-2016-0001734 filed on Jan. 6, 2016in the Korean Intellectual Property Office, the disclosure of which isincorporated by reference herein in its entirety.

BACKGROUND Field

The present disclosure relates generally to a video content providingapparatus for providing video content to be displayed as an image onvarious display apparatus such as a television (TV), a monitor, etc., acontrol method thereof, and a system, and for example, to a videocontent providing apparatus, which has an improved structure to preventand/or reduce an image display program caused by a mismatch of supportvideo interface between a relay and a display apparatus when videocontent is provided to the display apparatus not directly but via thelike relay such as an audio/video (AV) receiver, a control methodthereof and a system.

Description of Related Art

To compute and process predetermined information in accordance withcertain processes, an electronic apparatus basically includes a centralprocessing unit (CPU), a chipset, a memory, and the like electroniccomponents for computation. Such an electronic apparatus may beclassified variously in accordance with what information will beprocessed therein. For example, the electronic apparatus is classifiedinto an information processing apparatus such as a personal computer, aserver or the like for processing general information, and an imageprocessing apparatus for processing image information.

The image processing apparatus receives a content signal including imagedata from the exterior and processes the image data extracted from thecontent signal in accordance with various image processing processes.The image processing apparatus may display an image based on theprocessed image data on its own display panel, or output the processedimage data to another display apparatus provided with a panel so that onthe corresponding display apparatus can display an image based on theprocessed image signal. In particular, the image processing apparatusthat has a display panel is called a display apparatus, and may forexample includes a TV, a monitor, a portable multimedia player (PMP), atablet computer, a mobile phone, etc. Further, the image processingapparatus includes an apparatus for providing video data to anotherimage processing apparatus such as a TV, which is called a video contentproviding apparatus, a video providing apparatus, etc. As an example ofthe video content providing apparatus, there is an ultrahigh definition(UHD) player. For example, video content reproduced in a UHD player isprovided to the TV in accordance with preset interface standards, andthen displayed as an image on the TV.

The video content providing apparatus is directly connected to anotherimage processing apparatus and provides content without any separatedevice. However, due to various environmental reasons, convenience ofuse, etc., there may be a structure where video content is primarilytransferred from the video content providing apparatus the relay andthen secondarily transferred from the relay to one or more displayapparatuses. The relay not only transfers the video content to thedisplay apparatus but also performs various processes with respect tovideo content. Such a process may for example include authentication forsecurity of video content, scrambling, descrambling, etc.

To make the display apparatus display an image with the best quality,the video content providing apparatus may output video content with thehighest quality supportable in the display apparatus. However, if thereis a mismatch in ability to process video content between the relay andthe display apparatus, video content may be not normally transferredfrom the relay to the display apparatus or not transferred at all. As aresult, the display apparatus cannot normally display an image in thiscase. Therefore, it is important to overcome the mismatch and assurenormal display of video content.

SUMMARY

A video content providing apparatus is provided, the video contentproviding apparatus including: an output portion comprising outputcircuitry configured to transmit a content signal for displaying animage to a relay connected to an image processing apparatus to providethe content signal to the image processing apparatus; and at least oneprocessor configured to receive video formation information about afirst video format supported by the image processing apparatus among aplurality of video formats from the relay, and if it is determined thatthe relay does not support the first video format, to output the contentsignal corresponding to a second video format different from the firstvideo format and supportable by the relay, among the plurality of videoformats. Thus, even if the relay does not support the first videoformat, it is possible to prevent and/or avoid a situation in which theimage processing apparatus cannot display an image based on a contentsignal.

The plurality of video formats may be different in image quality fromone another. Thus, if the relay does not support the first video format,the image processing apparatus can display an image based on the secondvideo format instead of the first video format.

The image quality may depend on at least one of a resolution and framesper second.

The content signal may be transmitted in accordance with presetinterface standards, and the at least one processor may determine thatthe relay supports the first video format if the relay supports presetfirst-version interface standards, and determines that the relay doesnot support the first video format if the relay does not support thepreset first-version interface standards. Thus, it is easy to determinewhether the video format of the content signal is supported.

The at least one processor may transmit a command based on thefirst-version interface standard to the relay, and may determine thatthe relay supports the first-version interface standards if a reply tothe command is received from the relay within a preset period of time,but determines that the relay does not support the first-versioninterface standards if a reply to the command is not received from therelay within the preset period of time.

The at least one processor may access a preset address designated in thefirst-version interface standards of the relay to determine whether datadesignated corresponding to the address is acquirable, and may determinethat the relay supports the first-version interface standards if thedata is acquirable, but may determine that the relay does not supportthe first-version interface standards if the data is not acquirable.

The interface standards may include high definition multimedia interface(HDMI).

The first-version interface standards may include HDMI 2.0.

The at least one processor may determine that the relay supports HDMI2.0 if the relay can perform communication using a status and controldata channel (SCDC), but may determine that the relay does not supportHDMI 2.0 if the relay cannot perform communication using the SCDC.

The interface standards may include high-bandwidth digital contentprotection (HDCP).

The first-version interface standards may include HDCP 2.2.

The at least one processor may communicate with the relay based on theinterface standards through a cable for connecting the output portionand the relay.

The output portion may be configured to wirelessly communicate with therelay, and the at least one processor may wirelessly communicate withthe relay based on the interface standards.

The video format information may include extended display identificationdata (EDID) received from the image processing apparatus and stored inthe relay, and the at least one processor may acquire the EDID from therelay.

The at least one processor may output the content signal correspondingto the first video format if it is determined that the relay supportsthe first video format. Thus, if it is determined that the relaysupports the first video format, the image processing apparatus candisplay an image based on the first video format.

A method of controlling a video content providing apparatus is provided,the method including: receiving video formation information about afirst video format supported by an image processing apparatus among aplurality of video formats from a relay connected to the imageprocessing apparatus; determining whether the relay supports the firstvideo format; generating a content signal corresponding to a secondvideo format different from the first video format and supportable bythe relay, among the plurality of video formats if it is determined thatthe relay does not support the first video format; and transmitting acontent signal for displaying an image to the relay to provide thecontent signal to the image processing apparatus. Thus, even if therelay does not support the first video format, it is possible to preventand/or avoid a situation in which the image processing apparatus cannotdisplay an image based on a content signal.

A system is provided, the system including: a video content providingapparatus configured to provide a content signal; an image processingapparatus configured to display an image based on the content signal;and a relay configured to relay the content signal from the videocontent providing apparatus to the image processing apparatus, the videocontent providing apparatus including: an output portion comprisingoutput circuitry configured to transmit the content signal to the relay;at least one processor configured to receive video formation informationabout a first video format supported by the image processing apparatusamong a plurality of video formats from the relay, and if it isdetermined that the relay does not support the first video format, tooutput the content signal corresponding to a second video formatdifferent from the first video format and supportable by the relay,among the plurality of video formats. Thus, even if the relay does notsupport the first video format, it is possible to prevent and/or avoid asituation in which the image processing apparatus cannot display animage based on a content signal.

The at least one processor may output the content signal correspondingto the first video format if it is determined that the relay supportsthe first video format. Thus, if the relay does not support the firstvideo format, the image processing apparatus can display an image basedon the second video format instead of the first video format.

The relay may store the video format information received from the imageprocessing apparatus, and may transmit the stored video formatinformation to the video content providing apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects and attendant advantages of the presentdisclosure will become apparent and more readily appreciated from thefollowing detailed description, taken in conjunction with theaccompanying drawings, in which like reference numerals refer to likeelements, and wherein:

FIG. 1 is a diagram illustrating an example system according to a firstexample embodiment;

FIG. 2 is a block diagram illustrating an example source deviceaccording to the first example embodiment;

FIG. 3 is a block diagram illustrating an example high definitionmultimedia interface (HDMI) standard applied to the system according tothe first example embodiment;

FIG. 4 is a signal flowchart illustrating example high-bandwidth digitalcontent protection (HDCP) authentication between an HDCP transmitter andan HDCP receiver in the system according to the first exampleembodiment;

FIG. 5 is a diagram illustrating an example of a principle that thesource device according to the first example embodiment transmits acontent signal of a video format corresponding to processing ability ofa sink device;

FIG. 6 is a flowchart illustrating an example of the source deviceaccording to the first example embodiment providing video content to thesink device;

FIG. 7 is a block diagram illustrating example connections in a systemaccording to a second example embodiment;

FIG. 8 is a block diagram illustrating an example principle that an AVreceiver outputs signals to a TV and a loudspeaker device respectivelyin the system according to the second example embodiment;

FIG. 9 is a diagram illustrating an example of a principle that a sourcedevice transmits a content signal of a video format corresponding toprocessing ability of a sink device in the system according to thesecond example embodiment;

FIG. 10 is a flowchart illustrating an example source device providing acontent signal in a system according to a third example embodiment;

FIG. 11 is a diagram illustrating an example of a part of HDMI forumvendor-specific data block (HF-VSDB) in HDMI 1.4 applied to a systemaccording to a fourth example embodiment;

FIG. 12 is a diagram illustrating an example of a part of HF-VSDB inHDMI 2.0 applied to the system according to the fourth exampleembodiment;

FIG. 13 is a flowchart illustrating an example of determining whether asource device according to the fourth example embodiment supports HDMI2.0 of an AV receiver;

FIG. 14 is a diagram illustrating an example of a field of 0x01 bytes, afield of 0x21 bytes and a field of 0x40 and 0x41 bytes in a status andcontrol data channel (SCDC) structure of HDMI 2.0 applied to a systemaccording to a fifth example embodiment;

FIG. 15 is a flowchart illustrating an example of determining whether asource device according to the fifth example embodiment supports HDMI2.0 of an AV receiver;

FIG. 16 is a diagram illustrating an example of a part of an address mapapplied to the HDCP according to the fifth example embodiment;

FIG. 17 is a flowchart illustrating an example of determining whetherthe source device according to the fifth example embodiment supportsHDCP 2.2 of the AV receiver;

FIG. 18 is a flowchart illustrating an example in which a source deviceaccording to a sixth example embodiment provides a content signal to asink device through an AV receiver;

FIG. 19 is a diagram illustrating an example of a system according to aseventh example embodiment;

FIG. 20 is a signal flowchart illustrating an example source deviceproviding a content signal to a sink device through an AV receiver inthe system according to the seventh example embodiment;

FIG. 21 is a diagram illustrating an example of a system according to aneighth example embodiment;

FIG. 22 is a flowchart illustrating an example source device accordingto the eighth example embodiment providing a content signal to a sinkdevice through an AV receiver;

FIG. 23 is a block diagram illustrating an example principle that asource device determines support standards of an AV receiver in a systemaccording to a ninth example embodiment;

FIG. 24 is a flowchart illustrating an example source device accordingto the ninth example embodiment providing a content signal to a sinkdevice through the AV receiver;

FIG. 25 is a block diagram illustrating an example principle that an AVreceiver processes extended display identification data (EDID) of a sinkdevice in a system according to a tenth example embodiment;

FIG. 26 is a diagram illustrating an example in which the AV receivermodifies the EDID of the sink device in the system according to thetenth example embodiment; and

FIG. 27 is a flowchart illustrating an example in which the AV receiveraccording to the tenth example embodiment modifies the EDID and sendsthe modified EDID to the source device.

DETAILED DESCRIPTION

Below, various example embodiments will be described in greater detailwith reference to accompanying drawings. The following descriptions ofthe example embodiments are made by referring to elements illustrated inthe accompanying drawings, in which like numerals refer to like elementshaving substantively the same functions.

In the description of the example embodiments, an ordinal number used interms such as a first element, a second element, etc. is employed fordescribing variety of elements, and the terms are used fordistinguishing between one element and another element. Therefore, themeanings of the elements are not limited by the terms, and the terms arealso used just for explaining the corresponding embodiment withoutlimiting the idea of the disclosure.

Further, the example embodiments may describe only elements directlyrelated to the idea of the disclosure, and description of the otherelements may be omitted. However, it will be appreciated that theelements, the descriptions of which are omitted, are not unnecessary torealize the apparatus or system according to the example embodiments. Inthe following descriptions, terms such as “include” or “have” refer topresence of features, numbers, steps, operations, elements orcombination thereof, and do not exclude presence or addition of one ormore other features, numbers, steps, operations, elements or combinationthereof.

Further, the example embodiments respectively described with referenceto the accompanying drawings are not exclusive to each other unlessotherwise mentioned, and a plurality of embodiments may be selectivelycombined within one apparatus. The combination of these pluralembodiments may be discretionally selected and applied to realize thepresent disclosure by a person having an ordinary skill in the art.

FIG. 1 is a diagram illustrating an example system 1 according to afirst example embodiment.

As illustrated in FIG. 1, the system 1 according to the first exampleembodiment includes a video content providing apparatus 100 that outputsa video signal about video content, a display apparatus 200 thatdisplays an image by processing the video signal output from the videocontent providing apparatus 100, and an AV receiver 300 that relays avideo signal from the video content providing apparatus 100 to thedisplay apparatus 200. The video content providing apparatus 100 and thedisplay apparatus 200 are one-to-one connected to the AV receiver 300 bya cable, so that a video signal can be transferred from the videocontent providing apparatus 100 to the AV receiver 300 through the cableand transferred from the AV receiver 300 to the display apparatus 200.The video content providing apparatus 100, the display apparatus 200 andthe AV receiver 300 support common video interface standards so that avideo signal provided by the video content providing apparatus 100 canbe processed in the display apparatus 200.

The video content providing apparatus 100 reproduces video contentstored therein or receives video content from another external videosource 10. The name of the video content providing apparatus 100 isderived for convenience from an operation performed by the imageprocessing apparatus in this example embodiment, e.g., from a functionof providing video content to the display apparatus 200. Therefore, thevideo content providing apparatus 100 may be achieved without anylimitation. For example, the video content providing apparatus 100 maybe variously achieved by a player of an optical medium such as a digitalversatile disc (DVD) or Blu-ray; a UHD player; a set-top box; a TV; acomputer; a mobile device; a home theater system; or the like, but isnot limited thereto.

The display apparatus 200 may be variously achieved by a monitor, aportable multimedia player, a mobile phone, a tablet computer, anelectronic frame, an electronic blackboard, an electronic billboard, orthe like, but is not limited thereto, as well as the TV. In this exampleembodiment, the TV is used as the display apparatus 200 and receivesvideo content from the video content providing apparatus 100, but notlimited thereto. Alternatively, the apparatus for receiving videocontent may be achieved by not only various display apparatuses 200 butalso an image processing apparatus that cannot display an image byitself.

The display apparatus 200 receives video content from not only the videocontent providing apparatus 100 but also a separate video source 10.Further, the display apparatus 200 may be directly connected to thevideo content providing apparatus 100 without the AV receiver 300, anddirectly receive a video signal from the video content providingapparatus 100. Further, the method of transmitting a video signal is notlimited to the cable. Besides the cable, various methods may be used intransmitting a video signal. However, this example embodiment will bedescribed focusing on a system 1 where the AV receiver 300 relays videocontent from the video content providing apparatus 100 to the displayapparatus 200 and a video signal is transmitted through the cable.

Below, elements of the video content providing apparatus 100 will bedescribed with reference to FIG. 2. For convenience, the video contentproviding apparatus 100 will be called a source device in terms ofproviding video content, and the display apparatus 200 will be called asink device in terms of receiving the video content.

FIG. 2 is a block diagram illustrating an example source device 100according to the first example embodiment.

As illustrated in FIG. 2, the source device 100 includes a processor 110for processing a content signal of video content, an output portion(e.g., including output circuitry) 120 for outputting the content signalprocessed by the processor 110, a user input (e.g., including inputcircuitry) 130 for receiving a user's input, a storage 140 for storingdata therein, and a central processing unit (CPU) 150 for controllingoperations and processing computation in the source device 100.

In this example embodiment, the CPU 150 is provided independently of,e.g., separated from the processor 110. However, the CPU 150 may beintegrated with various functional chipsets such as the processor 110and provided in the form of a single system-on-chip (SoC). In otherwords, such a single SoC may involve both the processor 110 and the CPU150.

The source device 100 and the sink device 200 are classified into theimage processing apparatus for performing video-content relatedprocesses, and thus include elements having common or similar functions.In light of roles, there is a difference between the source device 100and the sink device 200 in that the source device provides video contentand the sink device 200 receives and processes the video content. Inthis example embodiment, the sink device 200 is configured to display animage based on video content, but not limited thereto. Alternatively,the sink device 200 may output the received video content to anotherdevice for displaying an image. In this case, the sink device 200 mayserve as the source device with regard to another device.

The foregoing elements of the source device 100 schematically illustratethe basic elements of each device. It will be apparent that a powersupply (not shown) or the like elements are added when the device isrealized as an actual product. In this example embodiment, descriptionsabout matters not directly related to the present disclosure may beomitted.

Below, the elements of the source device 100 will be described ingreater detail.

The processor 110 may include various processing circuitry thatprocesses a content signal of video content stored in the storage 140 orreceived from the outside in accordance with preset processes undercontrol of the CPU 150. If the source device 100 is a UHD player, theprocessor 110 performs various processes such as packaging, scrambling,etc. in accordance with preset multimedia interface standards so that acontent signal can be output through the output portion 120.

The output portion 120 may include various circuitry that transmits acontrol signal processed by the processor 110 to the AV receiver 300.The output portion 120 may perform additional processes such asserializing separately from the processor 110, and may be designed toperform processes based on standards instead of the processor 110. Theoutput portion 120 may not only send a content signal to the AV receiver300 but also receive a control signal or the like received in the AVreceiver 300 to the CPU 150. Further, the output portion 120 may serveas a communication interface to exchange a signal with various externaldevices (not shown) as well as the AV receiver 300.

The user input 130 may include various circuitry that sends variouspreset control commands or information to the CPU 150 or the processor110 in accordance to a user's control or input. For example, the userinput 130 issues various events caused by a user's control based on theuser's intention to be served as a trigger for computations oroperations of the CPU 150.

The storage 140 stores various pieces of data under process and controlof the processor 110 or the CPU 150. The storage 140 may refer to agroup of various types of storage and perform deleting and updating thedata. The storage 140 includes a flash-memory, a hard-disc drive (HDD),a solid-state drive (SSD) or the like nonvolatile memory to preservedata regardless of system power of the source device 100; a read onlymemory (ROM) from which only data reading is allowed but updating,deleting and writing are impossible; a random access memory (RAM), abuffer or the like in which data related to computations and operationsof the processor 110 and the CPU 150 is stored temporarily e.g.,retained only while the system power is supplied.

Further, the storage 140 may be configured to read data of video contentfrom an optical medium such as a Blu-ray disc.

The CPU 150 may include various processing circuitry for performingcentral computation to operate general elements such as the processor110 in the source device 100, and plays a central role in basicallyparsing and calculating data. The CPU 150 internally includes aprocessor register (not shown) in which commands to be processed arestored; an arithmetic logic unit (ALU) (not shown) in charge of, forexample, comparison, determination and computation; a control unit (notshown) for internally controlling the CPU 150 to analyze and carry outthe commands; an internal bus (not shown); a cache (not shown); etc.

The CPU 150 performs computation needed for operating the elements ofthe processor 110. Alternatively, some elements of the processor 110 maybe designed to operate without the data computation of the CPU 150 oroperate by a separate microcontroller (not shown).

In the structure including such a source device 100, the source device100 reproduces video content to generate a content signal and outputsthe content signal to the AV receiver 300 in accordance with presetmultimedia interface standards, and the AV receiver 300 relays the videocontent to the sink device 200 in accordance with the multimediainterface standards. Thus, the sink device 200 processes a contentsignal provided from the source device 100, and displays an image on adisplay panel (not shown) if the sink device 200 has the display panel(not shown) outputs the content signal to another display apparatus (notshown) capable of displaying an image if the sink device 200 does nothave a display panel (not shown).

There are no limits to the multimedia interface standards by which thesource device 100 provides a control signal to the sink device 200. Forexample, the multimedia interface standards may include a highdefinition multimedia interface (HDMI). Below, the HDMI will bedescribed.

In the HDMI, transition minimized differential signaling (TMDS) is usedin a physical layer, high-bandwidth digital content protection (HDCP) isused to encrypt a signal for content security, extended displayidentification data (EDID) is used for authentication between devices,and a consumer electronics control (CED) is used in connection of systemcontrol. There is a little difference between HDMI 1.4 and HDMI 2.0. Forexample, standards not supported in HDMI 1.4 but newly supported in HDMI2.0 will be described below.

FIG. 3 is a block diagram illustrating example high definitionmultimedia interface (HDMI) standards applied to the system according tothe first example embodiment;

As illustrated in FIG. 3, TMDS is implemented from a source device 310to a sink device 320 through an HDMI cable in accordance with HDMI 1.4.The HDMI cable and connector form four differential pairs for TMDS dataand clock channels. These channels are used in transmitting video data,audio data and auxiliary data.

Further, HDMI includes a VESA display data channel (DDC) as an I2C basedcommunication channel. The DDC is used for exchanging environment andstate information between the source device 310 and the sink device 320.Additional CEC protocols offer high-level control functions between allAV products within the system. Additional HDMI Ethernet and audio returnchannels (HEAC) offer Ethernet-compatible data networking between theconnected devices and Audio Return Channel in reverse direction to theTMDS.

Video data, audio data and auxiliary data are transmitted through threeTMDS data channels. TMDS clocks based on a video pixel rate istransmitted through a TMDS clock channel, and used as a referencefrequency for data recovery in the three TMDS data channels by an HDMIreceiver. In the source device 310, TMDS encoding is performed byconverting 8 bits per TMDS data channel into a DC balanced, e.g.,transition-minimized sequence of 10 bits, and thus serial transmissionis achieved at a rate of 10 bits per TMDS clock.

Video data may have a pixel size of 24, 30, 36 or 48 bits. A defaultimage of 24-bit color depth is transmitted at the same TMDS clock rateas the pixel clock rate. The higher the color depth, the higher the TMDSclock rate. A video format of a TMDS rate lower than 25 MHz istransmitted by a pixel-repetition scheme.

To transmit the audio data and the auxiliary data through the TMDSchannel, the HDMI employs a packet structure. To achieve higherreliability for the audio data and control data, data may be transmittedas a word of 10 bits generated by a BCH error correction code and errorreduction coding.

The DDC is used when the source device 310 determines the performanceand characteristic of the sink device 320. The source device 310acquires EDID recorded in the EDID ROM of the sink device 320 throughthe DDC, and determines a performance level of the sink device 320 inaccordance with information of the acquired EDID.

The CEC connects all the source device 310 and the sink device 320 inthe system to one control line. On the contrary to the DDC formed one toone between the source device 310 and the sink device 320, the CECconnects all the devices in the system and is thus utilized by way ofexample in controlling all the devices through one remote controller.

HDMI 2.0 is similar to HDMI 1.4, but includes some differences. HDMI 2.0has a data transmission rate in the TMDS channel much faster than thatof HDMI 1.4, and supports the maximum bandwidth of 18 Gbps. Accordingly,HDMI 2.0 supports 4K 50p/60p video transmission and multi-channel audiotransmission of the maximum 32 channels. In case of HDMI 1.4, the numberof maximum frames is limited to 24 at a resolution of 4096×2160 andlimited to 30 at a resolution of 3820×2160. On the other hand, HDMI 2.0supports up to 60 frames at a 4K resolution.

HDMI 2.0 supports up to 1536 kHz audio sampling rate, and supports anaspect ratio of 21:9. Further, HDMI 2.0 more extends CEC than HDMI 1.4and newly supports status and control data channel (SCDC) standards.

Like the DDC, the SCDC is an I2C based communication channel. The SCDCrefers to a one-to-one communication protocol for data exchange betweenthe source device 310 and the sink device 320. The SCDC uses the sameI2C standards as HDMI 1.4 in order to read the EDID and otherinformation. The SCDC extends I2C standards by providing a mechanism forthe sink device 320 to make a request for a state check to the sourcedevice 310.

The sink device 320 including the SCDC has to include a valid HDMI forumvendor-specific data block (HF-VSDB) in the EDID, and has to set a valueof SCDC_Present bit to 1. Before accessing the SCDC, the source device310 checks whether the sink device 320 includes the valid HDMI HF-VSDBin the EDID where the value of SCDC_Present bit is set to 1. If thevalue of SCDC_Present bit is not 1, the source device 310 does notaccess the SCDC. The SCDC_Present bit for determining whether the SCDCis supported or not will be described later.

Below, standards of an image displayable in the sink device 320 will bedescribed.

In terms of resolutions, an image is classified into standard definition(SD), full high definition (FHD) and ultrahigh definition (UHD) inaccordance with frame resolutions. The resolutions are high in order ofthe UHD, FHD and SD.

FHD has a resolution at least two times higher than SD and shows a moredetailed image than an analog TV or a general DVD. FHD supports aresolution of 1920×1080, and supports progressive scanning more improvedthan interlace scanning.

UHD or super hi-vision (SHV) includes 4K UHD supporting a resolution of3840×2160 and 8K UHD supporting a resolution of 7680×4320. UHD does notsupport the interlace scanning but supports only the progressivescanning. UHD provides that 10 bits or 12 bits are assigned per channelto represent colors.

In transferring video content from the source device to the sink devicebased on HDMI standards, a high transfer rate is more required for UHDvideo content than SD or FHD video content. In other words, HDMI 1.4 issuitable for transferring SD or FHD video content, but there may be aneed of HDMI 2.0 to transfer UHD video content. Although HDMI 1.4 iscapable of transferring 4K UHD video content, video content of 60 Hz isdifficult for HDMI 1.4 and there is a need of HDMI 2.0.

Another point to be considered in transferring 4K UHD or higher videocontent is application of the HDCP.

The HDCP encrypts content to be transferred, after the HDCP devices areauthenticated in the system. The authentication may be performed in theDDC and include a process of checking whether all the devices arelicensed and authorized to receive content. If the authentication issuccessful, the source device encrypts TMDS to thereby prevent contentfrom leaking during the transfer. Basically, the HDCP includes threesequences of authentication, encryption and destruction.

A one-to-one, e.g., point-to-point HDCP link may use only one HDCPtransmitter and one HDCP receiver. Therefore, if a relay is interposedin between an HDCP transmitter and an HDCP receiver, the relay has toencrypt the content again for each HDCP receiver. If the HDCP is appliedto the HDMI, the HDCP transmitter is regarded as the source device, theHDCP receiver is regarded as the sink device, and the relay is regardedas the AV receiver or repeater. The HDCP related to the relay of theHDMI will be described later.

FIG. 4 is a signal flowchart illustrating example high-bandwidth digitalcontent protection (HDCP) authentication between an HDCP transmitter 330and an HDCP receiver 340 in the system according to the first exampleembodiment.

As illustrated in FIG. 4, the HDCP authentication is performed betweenthe HDCP transmitter 330 and the HDCP receiver 340 in accordance withHDCP 1.x. The HDCP transmitter 330 and the HDCP receiver 340 have theirown unique private keys and public keys, respectively.

At operation S110 the HDCP transmitter 330 transmits a message includinga public key Aksv to the HDCP receiver 340.

At operation S120 the HDCP receiver 340 transmits a public key Bksv tothe HDCP transmitter 330.

At operation S130 the HDCP transmitter 330 checks whether the public keyof the HDCP receiver 340 is valid, and computes a secret key Km based onthe public key and private key of the HDCP receiver 340.

At operation S140 the HDCP receiver 340 checks whether the public key ofthe HDCP transmitter 330 is valid, and computes a secret key Km′ basedon the public key and private key of the HDCP transmitter 330. Thesecret keys Km and Km′ are respectively computed in the HDCP transmitter330 and the HDCP receiver 340, and not transmitted through communicationports.

At operation S150 the HDCP transmitter 330 generates a message ROencrypted by the secret key Km.

At operation S160 the HDCP receiver 340 generates a message RO′encrypted by the secret key Km′.

At operation S170 the HDCP receiver 340 transmits the message RO′ to theHDCP transmitter 330 before a preset period of time elapses for example,within 100 ms from time of first connection with the HDCP transmitter330. If no message is received even after the preset period of timepasses, the authentication is failed. Of course, such a specificnumerical value of ‘100 ms’ may be designed variously.

At operation S180 the HDCP transmitter 330 compares RO and RO′ andperforms the authentication in accordance with comparison results. If ROand RO′ are matched with each other, it means that Km and Km′ are alsoequal to each other and thus the authentication is successful. If RO andRO′ are not matched with each other, it means that Km and Km′ aredifferent from each other and thus the authentication is failed.

If the authentication is successful, at operation S190 the HDCPtransmitter 330 encrypts a content signal and transmits the encryptedcontent signal to the HDCP receiver 340. The secret key or the privatekey is not transmitted through an HDCP port, and only the public keyAksv or Bksv or the encrypted data traffic RO′ is exposed during thetransmission.

With development of HDCP 2.0 and HDCP 2.2, the authentication and otherdetails have been also changed. Since HDCP 2.0, all interactive digitalcommunication systems are applicable without being limited to specificinterfaces such as HDMI, DVI, DisplayPort, etc. In HDCP 2.0, a locationdetecting function was added to an authentication protocol so thatcontent can be transmitted to and received from only nearby devices atwireless connection. Further, ad-hoc encryption system of 56 bits wasreplaced by standard algorithms of an AES system of 128 bits for contentencryption and an RSA system including keys of 1024 bits and 3072 bits.Further, the number of connectable devices was limited to 32.

HDCP 2.2 performs authentication in accordance with steps ofauthentication and key exchange (AKE), locality check and session keyexchange (SKE). In the step of AKE, the public key of the HDCP receiver340 is authenticated by the HDCP transmitter 330. In the step oflocality check, the HDCP transmitter 330 makes locality of content bycompelling a round trip time (RTT) in between a pair of messages not tobe longer than 20 ms. In the step of SKE, the HDCP transmitter 330exchanges a session key with the HDCP receiver 340. More specificmatters are referred to HDCP 2.2 standards, and thus detaileddescriptions will be omitted.

Thus, the source device authenticates the sink device in accordance withHDCP standards, encrypts a content signal, and transmits the contentsignal to the authenticated sink device in accordance with HDMIstandards.

However, the source device does not support only one kind of videostandards with respect to one piece of video content, but mayselectively generate contents signals corresponding to many videostandards and selectively provide a content signal. In this case, if thesource device generates and provides a content signal having the highestquality or level supportable in the sink device, it will be good to auser. Below, it will be described that the source device provides acontrol signal corresponding to the processing ability of the sinkdevice.

FIG. 5 is a diagram illustrating an example principle that a sourcedevice 350 according to the first example embodiment transmits a contentsignal of a video format corresponding to processing ability of a sinkdevice 360. In this example embodiment, the source device 350 and thesink device 360 are directly connected without the AV receiver.

As illustrated in FIG. 5, the source device 350 performs HDCPauthentication with respect to the sink device 360 if connection withthe sink device 360 is detected. When the HDCP authentication iscompleted, the source device 350 accesses EDID ROM 361 of the sinkdevice 360 through the DDC, and acquires EDID 362 recorded in an EDIDROM 361.

In this example embodiment, the HDCP authentication precedes analysis ofthe EDID, but not limited thereto. Alternatively, the analysis of theEDID may precede the HDCP authentication.

Besides accessing the EDID ROM 361 of the sink device 360 through theDDC, the source device 350 may make a request for the EDID 362 to thesink device 360 and the sink device 360 returns the EDID 362 of the EDIDROM 361 to the source device 350 in response to the request. Here, therequest and the return may be performed using another communicationchannel as well as the DDC of the HDMI.

The source device 350 determines a video format supportable in the sinkdevice 360 based on the EDID 362 acquired from the sink device 360. Ifthe EDID analysis precedes the HDCP authentication, the HDCPauthentication is performed after determining the video format.

The source device 350 processes content data 351, generates a contentsignal having the highest quality among the video formats supportable inthe sink device 360, encrypts the content signal, and transmits theencrypted content signal to the sink device 360.

Items of information recorded in the EDID of the sink device are asfollows. The EDID stored in the sink device includes information aboutvarious characteristics, environments or states of the sink device. Forexample, the information includes items such as the name of the sinkdevice, the ID of the sink device, a model number, a manufactured date,a serial number, the maximum display size of an image, an aspect ratio,a horizontal frequency, a vertical frequency, the highest resolution,gamma, display power management signaling (DPMS) mode support, asupportable video mode, a manufacturer, etc. Besides, the EDID mayinclude additional information as necessary.

When the EDID having such items is acquired from the sink device, thesource device checks a “supportable video mode” among the items of theEDID. The “supportable video mode” specifies a resolution and afrequency (Hz) of a video format supportable in the sink device. Thesource device selects the video format having the highest quality, andgenerates a content signal based on the selected format. For example, ifthe video format having the highest level recorded in the supportablevideo mode of the EDID has a resolution of 2160p and a frequency of 60Hz, the source device generates a content signal of 2160p 60 Hz.

Further, the source device may check the “maximum resolution” in theEDID. The “maximum resolution” refers to a resolution having the highestlevel among many video formats supportable in the sink device, which arerecorded in the “supportable video mode.”

In such a manner, the source device can provide video content having thehighest quality among qualities supportable in the sink device.

FIG. 6 is a flowchart illustrating an example source device according tothe first example embodiment providing video content to the sink device.

As illustrated in FIG. 6, at operation S210 the source device senses ordetects connection with the sink device.

At operation S220 the source device acquires EDID from the sink device.

At operation S230 the source device selects a video format having thehighest quality supportable by the sink device in the acquired EDID.

At operation S240 the source device performs the HDCP authenticationwith regard to the sink device. Details of the HDCP authentication arethe same as described above.

At operation S250 the source device determines whether the HDCPauthentication is successful. If the HDCP authentication fails, theprocess is stopped. On the other hand, if the HDCP authentication issuccessful, at operation S260 the source device generates a contentsignal in accordance with a selected video format. At operation S270 thesource device encrypts the content signal in accordance with HDCPstandards. At operation S280 the source device transmits the encryptedcontent signal to the sink device.

In this example embodiment, the analysis of the EDID precedes the HDCPauthentication. Alternatively, the HDCP authentication may precede theanalysis of the EDID.

In this example embodiment, a content signal is transferred underone-to-one connection between the source device and the sink device.However, in the system according to the HDMI standards, N-to-Nconnection may be possible in between a plurality of devices. To thisend, a repeater used as the AV receiver may be applied to the system asillustrated in FIGS. 1 and 2.

FIG. 7 is a block diagram illustrating example connections in a systemaccording to a second example embodiment.

As illustrated in FIG. 7, in the system according to the second exampleembodiment, a plurality of source devices 410 is connected to an inputterminal of an AV receiver 420. Each source device 410 may individuallyprovide video content to the AV receiver 420.

The AV receiver 420 has an output terminal to which a plurality of sinkdevices 430 is connected or a separate AV receiver 440 may be connected.Such a separate AV receiver 440 also has an output terminal to which asink device 450 is connected.

By such an N-to-N connection between the devices, the AV receiver 420receives a plurality of pieces of video content and individuallyprovides each video content to each sink device 430. The AV receivers420, 440 serve as content relays in between the plurality of sourcedevices 410 and the plurality of sink devices 430, 450. In other words,the AV receivers 420, 440 not only functions like the sink device withrespect to the source device, but also functions like the source devicewith respect to the sink device.

During the HDCP authentication, the authentication between the AVreceiver 420 and the source device 410 is performed, and theauthentication between the sink device 430 and the AV receiver 440 isalso performed. The AV receiver 420 processes the encrypted videocontent received from the source device 410, and encrypts the processedvideo content again to be provided to the sink device 430 and the AVreceiver 440.

The AV receiver 420, 440 may be applied to various use environments. Oneof the most general uses is a case where both a display apparatus fordisplaying an image and a loudspeaker for outputting a sound are usedtogether.

FIG. 8 is a block diagram illustrating an example principle that an AVreceiver 500 outputs signals to a TV 470 and a loudspeaker device 480respectively in the system according to the second example embodiment.

As illustrated in FIG. 8, a UHD player 460 is connected to an inputterminal of the AV receiver 500, and the TV 470 and the loudspeakerdevice 480 are connected to an output terminal of the AV receiver 500.The UHD player 460 is regarded as the source device, the TV 470 and theloudspeaker device 480 are regarded as the sink device.

In general, the TV 470 has been developed to have a larger screen anddisplay an image with a higher resolution. However, as the TV 470 getsslimmer and more lightweight, an element for outputting a sound islikely to become inferior to an element for displaying an image.Although the TV 470 includes a loudspeaker, the loudspeaker may beinadequate to support a multichannel sound of high quality. If a userwants a high-quality sound well-matched with a high-quality imagedisplayed on the TV 470, the loudspeaker device 480 separated from theTV 470 may be added to the system.

The AV receiver 500 includes a receiver 510 for receiving a contentsignal from the UHD player 460, a processor (e.g., including processingcircuitry) 520 for processing the content signal, a storage 530, atransmitter 540 for outputting the processed content signal to the TV470 and the loudspeaker device 480, and a CPU 550 for controllingoperations and computations of the AV receiver 500.

If the UHD player 460, the AV receiver 500, the TV 470 and theloudspeaker device 480 are connected to one another, the HDCPauthentication is performed between them. The AV receiver 500 performsthe authentication with regard to the UHD player 460, and furtherperforms the authentication with regard to each of the TV 470 and theloudspeaker device 480. During the authentication between the AVreceiver 500 and the UHD player 460, the AV receiver 500 may inform theUHD player 460 that the AV receiver 500 is not the sink device but arepeater. Further, the AV receiver 500 informs the UHD player 460 thatthe AV receiver 500 is connecting with the TV 470 and the loudspeakerdevice 480. Thus, the UHD player 460 determines a connectionrelationship between the devices in the system.

The receiver 510 receives then encrypted content signal from the UHDplayer 460 and transmits it to the processor 520. The processor 520decrypts the encrypted content signal, performs a preset process,encrypts the content signal again, and transmits the encrypted contentsignal to the transmitter 540.

In the processor 520, a deMUX or demultiplexer 521 performs a reverseoperation of the multiplexer (not shown). That is, the deMUX 521connects one input terminal with a plurality of output terminals, anddistributes a stream input to the input terminal to the respectiveoutput terminals in accordance with selection signals. For example, ifthere are four output terminals with respect to one input terminal, thedeMUX 521 may select each of the four output terminals by combination ofselection signals having two levels of 0 and 1.

The deMUX 521 extracts a video signal and an audio signal from a contentsignal. There may be many methods of extracting the signals. Forexample, the deMUX 521 extracts a video signal and an audio signal froma content signal in accordance with packet identifier (PID) given topackets in the content signal. In the content signal, signals areindependently compressed and packetized according to channels and thesame PID is given to the packets corresponding to one channel so as tobe distinguished from the packets corresponding to another channel. ThedeMUX 521 classifies the packets in the content signal according to thePID, and extracts the signals having the same PID.

In this example embodiment, the deMUX 521 demultiplexes the contentsignal output from the receiver 510 into a digital video signal and adigital audio signal, and sends a video signal to the transmitter 540and sends an audio signal to an audio amplifier 522.

The audio amplifier 522 amplifies an audio signal received from thedeMUX 521 and amplifies the audio signal, thereby transmitting theamplified audio signal to the transmitter 540. To this end, the audioamplifier 522 includes a pulse width modulation (PWM) processor (notshown) for outputting a PWM signal based on an audio signal, anamplifier (not shown) for amplifying the PWM signal output from the PWMprocessor (not shown), and an LC filter (not shown) for filtering thePWM signal amplified by the amplifier (not shown) by a predeterminedfrequency band to thereby demodulate the PWM signal.

The transmitter 540 receives a video signal and an audio signal from theprocessor 520, and transmits the video signal to the TV 470 and theaudio signal to the loudspeaker device 480. Thus, an image based onvideo content provided by the UHD player 460 is displayed on the TV 470,while a sound based on the same video content is output through theloudspeaker device 480.

In the system where the AV receiver serves as a relay between the sourcedevice and the sink device, the source device provides a content signalhaving the best video format supportable in the sink device. In thiscase, the EDID of the sink device is used, and this will be describedbelow.

FIG. 9 is a diagram illustrating an example principle that a sourcedevice 610 transmits a content signal of a video format corresponding toprocessing ability of a sink device 630 in the system according to thesecond example embodiment.

As illustrated in FIG. 9, a source device 610 is connected to an inputterminal of an AV receiver 620, and a sink device 630 is connected to anoutput terminal of the AV receiver 620. That is, the source device 610,the AV receiver 620 and the sink device 630 are connected in series. Asthe source device 610, the AV receiver 620 and the sink device 630 areconnected to one another, the HDCP authentication is performed betweenthe source device 610 and the AV receiver 620, and the HDCPauthentication is performed between the AV receiver 620 and the sinkdevice 630. If the authentication between all the devices is completed,the source device 610 prepares for providing a content signal.

The AV receiver 620 accesses the sink device 630 and uses EDID 631stored in the sink device 630 to thereby send information about the sinkdevice 630 to the source device 610. For example, the AV receiver 620accesses the sink device 630 and copies and stores the EDID 631 of thesink device 630 as EDID 421. Then, the source device 610 accesses the AVreceiver 620 and acquires the EDID 631 of the sink device 630 from theAV receiver 620. However, this method is nothing but an example.Alternatively, the AV receiver 620 may be designed to change or modifythe EDID 631 without copying the EDID 631 as it is.

The source device 610 determines video formats supportable in the sinkdevice 630 based on the EDID 631 of the sink device 630 acquired fromthe AV receiver 620. The source device 610 generates a content signalfrom content data 611 in accordance with the video format of the highestquality among the determined video formats, encrypts the generatedcontent signal, and sends the encrypted content signal to the AVreceiver 620.

The AV receiver 620 decrypts and processes the content signal receivedfrom the source device 610, encrypts the content signal again and sendsthe encrypted content signal to the sink device 630. Thus, the sinkdevice 630 receives video content having the best supportable videoformat from the source device 610 and displays an image based on thereceived video content.

By the way, if the source device 610 provides video content to the sinkdevice 630 not directly but via the AV receiver 620, HDMI standardmatching is required between the AV receiver 620 and the sink device630.

For example, suppose that the sink device 630 supports a 4K UHD videoformat of 2160p and 60 Hz. To receive a 4K UHD image, the sink device630 has to support HDMI 2.0 and HDCP 2.2. HDMI 1.4 has a transfer rateinadequate to transmit a content signal of a 4K UHD image, but HDMI 2.0is suitable for transmitting a content signal of a 4K UHD image sinceits data transfer rate is higher than that of HDMI 1.4. Further, HDCP2.2 is applied to the video content of the 4K UHD image in accordancewith preset protocols so as to prevent content leakage.

If the source device 610 and the sink device 630 are directly connectedto each other, the source device 610 acquires the EDID 631 from the sinkdevice 630 and transmits a content signal of a 4K UHD video format basedon the EDID 631 to the sink device 630.

Although the AV receiver 620 is interposed in between the source device610 and the sink device 630, there are no problems if both the AVreceiver 620 and the sink device 630 support HDMI 2.0 and HDCP 2.2. Inthis case, if the source device 610 transmits the content signal of the4K UHD video format to the AV receiver 620, the AV receiver 620processes the content signal and transmits the processed content signalto the sink device 630.

On the other hand, if the AV receiver 620 is inferior to the sink device630 with respect to the processing ability or supports HDMI and HDCPhaving lower versions than those of the sink device 630, problems mayarise. For instance, there may be a case where the AV receiver 620supports HDMI 1.4 and HDCP 1.x but the sink device 630 supports HDMI 2.0and HDCP 2.2.

In this case, the source device 610 determines that the sink device 630is capable of displaying a 4K UHD image based on the EDID 631 of thesink device 630 acquired from the AV receiver 620. Thus, the sourcedevice 610 transmits a content signal of a 4K UHD image to the AVreceiver 620. However, the AV receiver 620 cannot normally process thecontent signal of the 4K UHD image since is supports up to HDMI 1.4 andHDCP 1.x. Therefore, the sink device 630 receives no content signal fromthe AV receiver 620 and thus displays no image.

Since no image is displayed on the sink device 630, a user may thinkthat something is wrong with the sink device 630 since the user does notknow internal operations of the system. Further, if a user buys a newsource device 610, the user may think that the source device 610 is outof order. However, such a situation may occur when the AV receiver 620does not have the latest versions of the interface and securitystandards.

Of course, this problem may be solved if the AV receiver 620 is replacedby another one having the latest versions of the interface and securitystandards. However, it may be not easy for a user since the replacementof the AV receiver 620 costs money. Therefore, it is important to atleast avoid the situation that the sink device 630 displays no image,without changing the system.

Below, an embodiment of solving the foregoing problem will be described.

FIG. 10 is a flowchart illustrating an example in which a source deviceprovides a content signal in a system according to a third exampleembodiment.

As illustrated in FIG. 10, at operation S310 the source device detectsconnection with the AV receiver and the sink device.

At operation S320 the source device acquires the EDID of the sink devicefrom the AV receiver.

At operation S330 the source device determines the multimedia interfacestandards of the sink device based on the acquired EDID.

At operation S340 the source device determines the multimedia interfacestandards of the AV receiver. A method of determining the multimediainterface standards of the AV receiver will be described later.

At operation S350 the source device determines whether the AV receiveris capable of supporting the multimedia interface standards of the sinkdevice. If the AV receiver is capable of supporting the multimediainterface standards of the sink device, it means that the AV receiveralso processes the video format having the highest level processible inthe sink device. For example, the source device determines that the AVreceiver is capable of supporting the multimedia interface standards ofthe sink device, if the multimedia interface standards of the AVreceiver has a version equal to or higher than that of the sink device.

If it is determined that the AV receiver is capable of supporting themultimedia interface standards of the sink device, at operation S360 thesource device determines that the previously acquired EDID is reliable,and selects a video format having the highest level supportable in thesink device as designated in the EDID.

On the other hand, if it is determined that the AV receiver is notcapable of supporting the multimedia interface standards of the sinkdevice, at operation S370 the source device determines that thepreviously acquired EDID is not reliable, and selects a video formathaving the highest level supportable in the AV receiver regardless ofthe EDID. Further, at operation S370 the source device may select avideo format lower by a preset level than the video format having thehighest level supportable in the sink device.

At operation S380 the source device generates a content signal inaccordance with the selected video format and transmits the generatedcontent signal to the AV receiver.

According to an example embodiment, the source device does notunconditionally take the EDID of the sink device acquired from the AVreceiver into account, but additionally determines the processingability of the AV receiver, thereby providing a content signal of avideo format having the highest level processible by the AV receiver inaccordance with the determination results.

If the AV receiver has the processing ability equal to or higher thanthat of the sink device, e.g., if the multimedia interface standards ofthe AV receiver has a version equal to or later than the multimediainterface standards of the sink device, the sink device can receive acontent signal of a video format having the highest level processible byitself.

On the other hand, if the AV receiver has the processing ability lowerthan that of the sink device, e.g., if the multimedia interfacestandards of the AV receiver has a version earlier than the multimediainterface standards of the sink device, the sink device cannot avoiddisplaying no image even though it receives a content signal of a videoformat having the highest level processible by itself.

To determine the multimedia interface standards of the sink device, thesource device takes the EDID into account. Below, the method that thesource device determines the multimedia interface standards of the AVreceiver will be described.

In this example embodiment, HDMI will be described as the multimediainterface standards, but this is nothing but an example. That is, thepresent disclosure is not limited to only HDMI. Further, in thisembodiment, HDCP will be described as content security standards inconnection with HDMI since HDCP is related to HDMI in accordance withthe video formats as described above. For example, HDMI 2.0 and HDCP 2.2have to be supported to process a video format of 4K UHD. If support ofone between HDMI 2.0 and HDCP 2.2 means support of the other one, it maybe determined that either of HDMI 2.0 or HDCP 2.2 is supported.

A main difference between HDMI 2.0 and HDMI 1.4 is whether SCDC issupported or not.

FIG. 11 is a diagram illustrating an example of a part of HDMI forumvendor-specific data block (HF-VSDB) 710 in HDMI 1.4 applied to a systemaccording to a fourth example embodiment.

As illustrated in FIG. 11, HF-VSDB 710 in HDMI 1.4 includes eight bitsfrom 0 to 7 with respect to each of bytes. In this embodiment, a part ofHF-VSDB 710 is shown from the 0th bytes to the 6th bytes.

Here, the 7th bit of the 6th bytes refers to Supports_AI bit 711. If thesink device supports a function using information transmitted by audiocontent protection (ACP), ISRC1 and ISRC2 packets, Supports_AI bit 711is set to ‘1’. Otherwise, Supports_AI bit 711 is set to ‘0’. The ACPpacket is used by the source device to transmit information aboutcontent related to an active audio stream. The international standardrecording code (ISRC) packet is an international standard code foridentifying an album and music video recording defined by aninternational standardization organization (ISO) 3901.

For example, Supports_AI bit 711 in HDMI 1.4 is a bit for activatingprocess of an audio signal, which is generally set to ‘1’ if an audioprocess is needed.

The 7th bit of the 6th bytes in HDMI 2.0 is different in meaning fromthat in HDMI 1.4.

FIG. 12 is a diagram illustrating an example of a part of HF-VSDB 720 inHDMI 2.0 applied to the system according to the fourth exampleembodiment.

As illustrated in FIG. 12, HF-VSDB 720 in HDMI 2.0 includes eight bitsfrom 0 to 7 with respect to each of bytes. In this example embodiment, apart of HF-VSDB 720 is shown from the 0th bytes to the 6th bytes.

The 7th bit of the 6th bytes refers to SCDC_Present bit 721. If SCDC issupported, SCDC_Present bit 721 is set to ‘1’. If SCDC is not supported,SCDC_Present bit 721 is set to ‘0’.

The address of SCDC_Present bit 721 in HDMI 2.0 is equal to the addressof Supports_AI bit 711 (see FIG. 11) in HDMI 1.4. In other words, thesame address has different meanings in accordance with versions of HDMI.

If the 7th bit of the 6th bytes is ‘1’ when the source device acquiresHF-VSDB from the AV receiver, the source device may incorrectlydetermine that the AV receiver supports HDMI 2.0 even though the AVreceiver supports HDMI 1.4.

In this case, the source device performs communication with the AVreceiver through the SCDC and determines whether the AV receiversupports the SCDC in accordance with responses of the AV receiver.

For example, the source device accesses a preset address of the AVreceiver through SCDC. If the AV receiver supports the SCDC, the sourcedevice can acquire desired information from the corresponding address.On the other hand, if the AV receiver does not support the SCDC, thesource device cannot found the address or cannot acquire desiredinformation from the address.

Further, the source device may transmit a preset message to the AVreceiver through the SCDC. If the AV receiver supports the SCDC, thesource device can receive a response to the message from the AV receiverwithin a preset period of time. On the other hand, if the AV receiverdoes not support the SCDC, the source device cannot receive any responseto the message from the AV receiver.

If it is determined that the AV receiver supports the SCDC, the sourcedevice determines that the AV receiver supports HDMI 2.0. Further, if itis determined that the AV receiver does not support the SCDC, the sourcedevice determines that the AV receiver supports HDMI 1.4 or earlierversion.

FIG. 13 is a flowchart illustrating an example of determining whether asource device according to the fourth example embodiment supports HDMI2.0 of an AV receiver.

As illustrated in FIG. 13, at operation S410 the source device acquiresHF-VSDB from the AV receiver.

At operation S420 the source device determines whether the 7th bit ofthe 6th bytes in the acquired HF-VSDB is ‘1’.

If it is determined that the 7th bit of the 6th bytes in the acquiredHF-VSDB is ‘1’, at operation S430 the source device performscommunication with the AV receiver through the SCDC. On the other hand,if it is determined that the 7th bit of the 6th bytes in the acquiredHF-VSDB is not ‘1’, the source device moves to operation S460.

At operation S440 the source device determines whether the communicationwith the AV receiver through the SCDC is successful. Here, there may bevarious methods of determining whether the communication using the SCDCbetween the source device and the AV receiver is successful. Forexample, the source device transmits a preset command based on the SCDCto the AV receiver, and determines that the communication using the SCDCis successful if a response to the command is received within a presetperiod of time but determines that the communication using the SCDC isfailed if a response to the command is not received within the presetperiod of time. Besides, the source device may determines that thecommunication using the SCDC is successful if information designated inthe SCDC standards is acquired from the address of the AV receiverdesignated in the SCDC standards.

If it is determined that the communication with the AV receiver throughthe SCDC is successful, at operation S450 the source device determinesthat the AV receiver supports the SCDC and thus determines that the AVreceiver supports HDMI 2.0.

On the other hand, if it is determined that the communication with theAV receiver through the SCDC is failed, at operation S460 the sourcedevice determines that the AV receiver does not support the SCDC andthus determines that the AV receiver does not support HDMI 2.0.

In this manner, the source device can determine whether or not the AVreceiver supports HDMI 2.0. However, the method of determining whetherthe AV receiver supports HDMI 2.0 is not limited to the foregoingexample embodiment.

For example, an address map having an SCDC structure supported by HDMI2.0 designates ‘Offset’ for indicating an address, ‘R/W’ for indicatingwhether reading or writing is possible, and ‘Name’ of informationrecorded in each address.

The source device can access the AV receive and acquire information atan address in accordance with the address recorded in the address map ofthe SCDC structure. Here, the source device determines whether the AVreceiver supports the SCDC and supports HDMI 2.0 based on informationabout Sink Version recorded in an address of 0x01, Scramber_Statusrecorded in an address of 0x21, or Status_Flags_0 and Status_Flags_1recorded in addresses of 0x40 and 0x41.

FIG. 14 is a diagram illustrating an example of a field 740 of 0x01bytes, a field 750 of 0x21 bytes and a field 760 of 0x40 and 0x41 bytesin a status and control data channel (SCDC) structure of HDMI 2.0applied to a system according to a fifth example embodiment.

As illustrated in FIG. 14, the AV receiver playing as a role of the sinkdevice sets a proper value for a sink version field 740 in the SCDCstructure. In a relationship between the source device and the AVreceiver, the AV receiver receives a content signal from the sourcedevice and therefore functions like the sink device. The source devicereads this field 740 to determine the version of the sink device.

Regarding each bit in Scrambler Status Register, the AV receiver playingas the role of the sink device resets the bits to ‘0’ when there are nopower signals of +5V from the source device or when a hot plug detect(HPD) pin has a low voltage for more than 100 ms.

Scrambling_Status bit in the field 750 of 0x21 bytes is set to ‘1’ ifthe AV receiver playing as the role of the sink device detects ascrambled control code sequence, but set to ‘0’ if the AV receiver doesnot detect the scrambled control code sequence. The foregoing scramblingis different from encryption of the HDCP security standards and appliedwhen the source device transmits a content signal in accordance with theHDMI standards.

Regarding each bit of Status Flags Register, the AV receiver playing asthe role of the sink device resets the bit to ‘0’ when there are nopower signal of +5V from the source device or when the HPD pin has a lowvoltage for more than 100 ms.

Clock_Detected bit is set to ‘1’ if the AV receiver regarded as the sinkdevice detects a valid clock signal, but set to ‘0’ otherwise.

Ch0_Locked bit is set to ‘1’ if the AV receiver regarded as the sinkdevice successfully decodes data in the HDMI 0th channel, but set to ‘0’otherwise.

Ch1_Locked bit is set to ‘1’ if the AV receiver regarded as the sinkdevice successfully decodes data in the HDMI 1st channel, but set to ‘0’otherwise.

Ch2_Locked bit is set to ‘1’ if the AV receiver regarded as the sinkdevice successfully decodes data in the HDMI 2nd channel, but set to ‘0’otherwise.

The source device determines that the AV receiver supports the SCDC ifit is possible to access the AV receiver and acquire desired informationfrom the address provided in the SCDC structure. Further, the sourcedevice determines that the AV receiver does not support the SCDC if itis impossible to access the address provided in the SCDC structure oracquire desired information from the address.

Thus, the source device can determine whether the AV receiver supportsHDMI 2.0.

FIG. 15 is a flowchart illustrating an example of determining whether asource device according to the fifth example embodiment supports HDMI2.0 of an AV receiver;

As illustrated in FIG. 15, at operation S510 the source device has anaccess to the AV receiver.

At operation S520 the source device accesses a preset address of the AVreceiver provided in the SCDC structure. The preset address provided inthe SCDC structure refers to an address expected to have informationproviding a basis for determining whether the SCDC is supported or not,details of which has been described as above.

At operation S530 the source device determines whether to have an accessto the preset address.

If it is accessible to the preset address, at operation S540 the sourcedevice acquires information from the preset address. On the other hand,it is not accessible to the preset address, the source device moves tooperation S570.

At operation S550 the source device determines whether the acquiredinformation is provided by the SCDC structure.

If it is determined that the acquired information is provided by theSCDC structure, at operation S560 the source device determines that theAV receiver supports not only the SCDC but also HDMI 2.0.

On the other hand, if it is determined that the acquired information isnot provided by the SCDC structure, at operation S570 the source devicedetermines that the AV receiver supports neither SCDC nor HDMI 2.0.

The AV receiver has to support at least HPCP 2.2 so as to process videocontent of a 4K UHD video format. The AV receiver supporting HDCP 2.2 isnot necessarily expected to support HDMI 2.0 since HDCP 2.2 isreasonably applied to HDMI 2.0 capable of processing 4K UHD videocontent. Below, a method of determining whether the AV receiver supportsHDCP 2.2 will be described in detail.

FIG. 16 is a diagram illustrating an example of a part of an address map770 applied to the HDCP according to the fifth example embodiment.

As illustrated in FIG. 16, the address map 770 applied to the HDCPincludes items such as Offset to show an address of a field, Name toshow a name of information recorded in each address, Size in Bytes toshow the size of a field, Rd/Wr to show whether reading or writing ispossible, Function to show content and functions of the information,etc. In case of Rd/Wr, Rd indicates that only reading of information ispossible, and Rd/Wr indicates that both reading and writing ofinformation are possible.

A field newly added to HDCP 2.2 is HDCP2Version recorded in an addressof 0x50. When an HPD signal is sensed, the AV receiver regarded as theHDCP receiver keeps a valid value of HDCP2Version to be readable by thesource device regarded as the HDCP transmitter. For example, the 2nd bitof this field shows whether the HDCP receiver supports HDCP 2.2. Forinstance, when this bit is set to ‘1’, the HDCP receiver supports HDCP2.2.

Therefore, the source device regarded as the HDCP transmitter has anaccess to the 2nd bit of the field having an address of 0x50 in the AVreceiver regarded as the HDCP receiver, and thus determines whether theAV receiver supports HDCP 2.2.

FIG. 17 is a flowchart illustrating an example of determining whetherthe source device according to the fifth example embodiment supportsHDCP 2.2 of the AV receiver.

As illustrated in FIG. 17, at operation S610 the source device accessesthe AV receiver.

At operation S620 the source device has an access to the 2nd bit of thefield having the address of 0x50 in the AV receiver.

At operation S630 the source device determines whether it is possible toaccess the foregoing address of the AV receiver.

If it is possible to access that address of the AV receiver, atoperation S640 the source device acquires information from that address.On the other hand, if it is impossible to access that address of the AVreceiver, the source device moves to operation S670.

At operation S650 the source device determines whether the acquiredinformation has a value of ‘1’.

If it is determined that the acquired information has a value of ‘1’, atoperation S660 the source device determines that the AV receiversupports HDCP 2.2. On the other hand, if it is determined that theacquired information does not have a value of ‘1’, at operation S670 thesource device determines that the AV receiver does not support HDCP 2.2.

As described above, the source device receives the EDID of the sinkdevice from the AV receiver, and determines at least one between themultimedia interface standards and content security standards of the AVreceiver, thereby determining whether the EDID is reliable in accordancewith the determination results.

For example, if it is recorded in the EDID of the sink device that HDMI2.0 and HDCP 2.2 are supported and a 4K UHD video format is processible,the source device determines whether the AV receiver supports at leastone of HDMI 2.0 and HDCP 2.2 before transmitting a 4K UHD content signalto the AV receiver.

If it is determined that the AV receiver supports at least one of HDMI2.0 and HDCP 2.2, the source device relies on the EDID and transmits a4K UHD content signal to the AV receiver in accordance with the EDID. Onthe other hand, if it is determined that the AV receiver supportsneither HDMI 2.0 nor HDCP 2.2, the source device does not rely on theEDID and transmits a content signal having a video format supported inHDMI 1.4, e.g., the previous version of HDMI 2.0 to the AV receiver.

Thus, the source device according to an example embodiment preventsand/or avoids a situation that the sink device displays no image, eventhough the AV receiver supports the standards having an older versionthan that of the sink device.

HDMI 2.0 is related to the multimedia interface, but HDCP 2.2 is relatedto security in content transfer. Strictly speaking, HDMI and HDCP aredifferent in standards from each other. However, since both high datatransfer rate and security in the transfer are required when the sourcedevice provides high resolution and high quality of video content, HDMI2.0 and HDCP 2.2 are generally applied together in an actual product.Therefore, the source device may be configured to determine whether theAV receiver supports at least one of HDMI 2.0 and HDCP 2.2.

However, for more accurate determination, the source device maydetermine whether all of HDMI 2.0 and HDCP 2.2 are supported. Below, anexample embodiment related to this will be described with reference toFIG. 18.

FIG. 18 is a flowchart illustrates an example source device according toa sixth example embodiment providing a content signal to a sink devicethrough an AV receiver.

As illustrated in FIG. 18, at operation S710 the source device detectsconnections with the AV receiver and the sink device.

At operation S720 the source device acquires the EDID of the sink devicefrom the AV receiver. To this end, the AV receiver accesses the sinkdevice and copies and stores the EDID from the sink device. In thisembodiment, suppose that the highest resolution supportable in the EDIDis 4K UHD.

At operation S730 the source device determines whether the AV receiversupports the SCDC.

If it is determined that the AV receiver supports the SCDC, at operationS740 the source device determines whether the AV receiver supports HDCP2.2. On the other hand, if it is determined that the AV receiver doesnot support the SCDC, the source device moves to operation S760.

If it is determined that the AV receiver supports HDCP 2.2, at operationS750 the source device determines the acquired EDID is reliable andtransmits a 4K UHD content signal to the AV receiver based ondesignation of the EDID. On other hand, if it is determined that the AVreceiver does not support HDCP 2.2, at operation S760 the source devicedetermines that the acquired EDID is unreliable, the source devicetransmits a content signal having a resolution of 1080p lower than theresolution designated in the EDID to the AV receiver.

Thus, the source device makes the sink device display an image properlywith reference to the standards supported in the AV receiver. Theoperation S730 and the operation S740 may be exchanged with each other.

In the foregoing example embodiments, the HDMI is given as themultimedia interface standards, but not limited thereto. For example,HDCP, e.g., the security standards for the content transfer is notlimited to only HDMI, and may be widely applicable to various multimediainterface standards. For example, the present disclosure may employwired or wireless interface standards to which the HDCP is applied, orwired or wireless interface standards to which the HDCP is not applied.

Further, the security standards for the content transfer are not limitedto only the HDCP.

In addition, the present disclosure may be achieved to determine onlyone of the content transfer security standards and the multimediainterface standards.

In the foregoing example embodiments, a content signal and a controlsignal are transferred between the source device and the AV receiverthrough a cable according to the HDMI standards. However, the presentdisclosure is not limited to these example embodiments, and thus anotherexample embodiment will be described below.

FIG. 19 is a diagram illustrating an example of a system according to aseventh example embodiment.

As illustrated in FIG. 19, the system according to the seventh exampleembodiment includes a source device 810, an AV receiver 820 and a sinkdevice 830. Details of the source device 810, the AV receiver 820 andthe sink device 830 are the same as described above, and thus repetitivedescriptions will not be repeated here.

The AV receiver 820 has an input terminal for connection with the sourcedevice 810, and an output terminal for connection with the sink device830. Here, the source device 810 is connected to the AV receiver 820through a cable 840 and transmits general signals through the cable 840.Separately from the cable 840, the source device 810 and the AV receiver820 may respectively use wireless communication modules 811 and 821 forwireless communication.

The source device 810 may transmit a control signal through the cable840 according to the multimedia interface standards. As an example ofthe multimedia interface standards, there is the HDMI, but themultimedia interface standards are not limited to the HDMI.

The wireless communication module 811, 821 performs wirelesscommunication corresponding to various protocols. These wirelesscommunication protocols include wireless fidelity (Wi-Fi), Wi-Fi Direct,Bluetooth, Universal Plug And Play (UPNP), Near Field Communication(NFC), etc. The wireless communication module 811, 821 includes variouscommunication circuitry, such as, for example, and without limitation,unit modules for communication based on protocols in accordance withsupport protocols.

Below, the foregoing protocols will be described schematically.

Wi-Fi refers to a protocol of supporting wireless local area networkbased on institute of electrical and electronics engineers (IEEE) 802.11and personal area network (PAN)/local area network (LAN)/wide areanetwork (WAN), etc. In an infrastructure mode, Wi-Fi provides wirelesscommunication relayed by access points (AP) in between devices. In caseof IEEE 802.11n, Wi-Fi guarantees the maximum transmission speed of 300Mbps. The AP is connected to a router accessing an exterior WAN, andforms a hot spot of a predetermined range within an unclosed space. Eachdevice is positioned within the hot spot around the AP and wirelesslyaccesses the AP, thereby connecting and communicating with a network viathe AP. Here, the range of the hot spot may be expanded by additionallyinstalling a device for amplifying a signal. However, it is not properfor a user to use Wi-Fi for the wireless communication while s/he ismoving since the hot spot generally has a narrow range.

Wi-Fi Direct refers to a protocol which is based on peer-to-peer (P2P)and does not use the AP in Wi-Fi. Based on Wi-Fi Direct, the displayapparatus 100 may directly connect and communicate with other deviceswithout using the AP. Wi-Fi Direct guarantees the maximum transmissionspeed of 250 Mbps within a distance of 200 m between the devices.

Wi-Fi Direct utilizes a technique related to Ad-hoc among Wi-Fitechniques. An ad-hoc network is a communication network establishedwith only mobile hosts without a stationary wired network. The ad-hocnetwork is suitable when it is difficult to establish the wired networkor when it is used for a short time after establishing the network. Thead-hoc network has advantages that the network is quickly andinexpensively established since there is no limit to move the host andthere is no need of a wired network and a base station. In the ad-hocnetwork, mobile nodes are used as not only hosts but also a kind ofrouter, and multi-paths are set up with regard to other nodes or a pathis dynamically set up. Wi-Fi Direct is a technique achieved to improvetransmission speed and security by remedying the ad-hoc technique'sshortcomings.

Wi-Fi Direct is fundamentally related to 1:1 connection, but 1:Nconnection is also possible. For instance, an image processing apparatushas the following processes in order to connect and communicate with themobile device or the like external device in accordance with a Wi-FiDirect protocol. The mobile device sends a connection request message tothe image processing apparatus by a push method. If the image processingapparatus accepts the connection request of the mobile device, a pairingis completed between the image processing apparatus and the mobiledevice.

Bluetooth is a direct communication method between devices based on IEEE802.15.1 standards. Bluetooth uses an industrial scientific and medical(ISM) frequency of 2400 to 2483.5 MHz. However, to prevent interferencewith other systems using higher and lower frequencies, Bluetooth employstotal 79 channels of 2402 to 2480 MHz except a band as much as 2 MHzafter 2400 MHz and a band as much as 3.5 MHz before 2483.5 MHz.

Since many systems use the same frequency band, electromagneticinterference is likely to occur between the systems. To prevent this,Bluetooth employs a frequency hopping technique. The frequency hoppingtechnique is to transmit a packet (data) little by little while movingin many channels quickly in accordance with certain patterns. Bluetoothhops over 79 assigned channels 1600 times per second. Communication isaccomplished when this hopping pattern is synchronized between Bluetoothdevices. Since Bluetooth devices are connected as a master and a slave,the communication is not achieved between the two devices if the slavedevice is not synchronized with frequency hopping generated by themaster device. Therefore, stable connection is expected withoutelectromagnetic interferences with other systems. For reference, onemaster device can connect with up to seven slave devices. Here,communication between the master device and the slave device ispossible, but communication between the slave devices is impossible.However, the roles of the master and the slave may be exchangeable witheach other according to situations since they are not fixed.

UPNP is a protocol for connecting devices by a P2P method in accordancewith digital living network alliance (DLNA). UPNP utilizes the existingprotocols such as Internet protocol, tape carrier package (TCP), userdatagram protocol (UDP), hypertext transfer protocol (HTTP), andextensible mark-up language (XML). UPNP is based on a wire protocol, inwhich information exchanged between devices is represented in the XMLand communicated through the HTTP.

Wi-Fi, Bluetooth or the like protocol uses 48-bit media access control(MAC) address as a unique identifier of a communication module, whereasUPNP uses an identifier of universally unique identifier (UUID). UUID isan identifier of 16 octets, e.g., 128 bits, and is represented by 32lowercase hexadecimal digits. UUID is a set of 32 characters or digits,represented by four hyphens, and has a total 36-digit number of“8-4-4-4-12”.

NFC is one of radio-frequency identifications (RFID), which is acontactless short-range wireless communication protocol using afrequency band of 13.56 MHz. NFC is a technique to exchange data betweendevices at a near distance of about 10 cm, which is extended fromISO/IEC 14443. NFC operates based on electromagnetic induction betweentwo adjacent loop antennas within a magnetic field.

NFC supports two modes of a passive communication mode and an activecommunication mode. In the passive communication mode, a starting deviceprovides a carrier field, and a target device operates while modulatingthe provided fields. The target device of the passive communication modeacquires operation power from the electromagnetic field provided by thestarting device, and thus the target device also serves as atransceiver. By the way, in the active communication mode, both thestarting device and the target device communicate with each other bygenerating electric fields in itself. In the active communication mode,one device releases its own electromagnetic field until receiving datafrom an opponent, and activates its own electromagnetic field whentransmitting data to the opponent.

FIG. 20 is a signal flowchart illustrating an example in which thesource device 810 provides a content signal to the sink device 830through the AV receiver 820 in the system according to the seventhexample embodiment. In FIG. 20, a solid line refers to a signal transferusing a wired line, and a dotted line refers to a signal transferthrough wireless communication.

As illustrated in FIG. 20, at operation S810 the source device 810performs pairing for wireless communication with the AV receiver 820.

At operation S820 the AV receiver 820 acquires and stores EDID of thesink device 830 from the sink device 830. In this example embodiment,the AV receiver 820 and the sink device 830 are wired-connected by acable.

At operation S830 the source device 810 acquires the EDID of the sinkdevice 830 from the AV receiver 820 through wireless communication.

At operation S840 the source device 810 makes a request for a replyabout whether the AV receiver 820 supports at least one of HDMI 2.0 andHDCP 2.2, through wireless communication.

At operation S850 the AV receiver 820 transmits the reply in response tothe request from the source device 810 through the wirelesscommunication.

For example, the source device 810 makes a preset request command basedon HDCP 2.2 to the AV receiver 820, and the AV receiver 820 returns thereply to the source device 810 in response to the request. The sourcedevice 810 determines that the AV receiver supports HDCP 2.2 if thereply is received within a preset period of time.

When the reply is received from the AV receiver 820, at operation S860the source device 810 generates a content signal in accordance with avideo format designated in the EDID and transmits the content signal tothe AV receiver 820 through the cable. Thus, at operation S870 the AVreceiver 820 transmits this content signal to the sink device.

On the other hand, if the source device 810 receives no reply from theAV receiver 820, at operation S880 the source device 810 generates acontent signal to have a video format supportable in HDMI 1.4 withoutreferring to the video format designated in the EDID, and transmits thiscontent signal to the AV receiver 820. Thus, at operation S890 the AVreceiver 820 transmits the received content signal to the sink device.

The source device and the AV receiver may be connected by only wirelesscommunication in accordance with design of the system, and an exampleembodiment related to this will be described.

FIG. 21 is a diagram illustrating an example of a system according to aneighth example embodiment.

As illustrated in FIG. 21, the system according to the eighth exampleembodiment includes a source device 840, an AV receiver 850 and a sinkdevice 860. Here, the AV receiver 850 and the sink device 860 arestationarily installed and used on a certain installation surface, andthe sink device 860 is connected an output terminal of the AV receiver850. On the other hand, the source device 840 is a mobile device, whichis easy to be carried by a user, and wireless communication between thesource device 840 and the AV receiver 850 is possible if the sourcedevice 840 enters a range of a hot spot within a preset distance fromthe AV receiver 850. The hot spot may be formed by the AV receiver 850itself, or may be formed by a separate wireless communication devicesuch as an access point (AP).

To provide a content signal to the sink device 860, the source device840 first enters the hot spot and thus the source device 840 and the AVreceiver 850 are paired for wireless communication. Then, the sourcedevice 840 acquires the EDID of the sink device 860 from the AV receiver850 through wireless communication, and determines a video format inaccordance with the multimedia interface standards of the AV receiver850. The source device 840 generates a content signal according to thedetermined video format, and transmits the content signal to the AVreceiver 850 through the wireless communication.

In terms of wireless communication protocols for connection between thesource device 840 and the AV receiver 850, the protocol supported by theAV receiver 850 may have an older version than the protocol supported bythe sink device 860. If a new protocol has a higher data transfer ratethan an old protocol, the new protocol may support transmission withregard to a video format of a relatively high resolution but the oldprotocol may support transmission with regard to a video format of not arelatively high resolution but a relatively low resolution.

In this case, even if the EDID of the sink device 860 supports a videoformat of a relatively high resolution, the AV receiver 850 cannotsupport the video formation having such a high resolution. Thus, thesource device 840 determines whether the AV receiver 850 supports thenew protocol, and selectively sends the AV receiver 850 one of a contentsignal having a video format based on the new protocol and a contentsignal having a video format based on the old protocol in accordancewith the determination results.

FIG. 22 is a flowchart illustrating an example source device accordingto the eighth example embodiment providing a content signal to a sinkdevice through an AV receiver;

As illustrated in FIG. 22, at operation S910 the source device and theAV receiver are paired with each other. In this embodiment, not wiredcommunication but wireless communication is performed between the sourcedevice and the AV receiver.

At operation S920 the source device receives the EDID of the sink devicefrom the AV receiver.

At operation S930 the source device determines whether the AV receiversupports the new protocol. There are many methods of determining whetherthe AV receiver supports the new protocol or the old protocol. Forexample, the source device may send a command based on the new protocolto the AV receiver, and determine whether the AV receiver supports thenew protocol, based on whether a reply to the corresponding command isreceived within a preset period of time.

If the AV receiver supports the new protocol, the AV receiver recognizesthe command based on the new protocol and thus makes a reply to thecommand. On the other hand, if the AV receiver supports only the oldprotocol, the AV receiver does not recognize the command based on thenew protocol and thus makes no reply to the command. Of course, theremay be a command to recognize in the old protocol among the commandsbased on the new protocol, and therefore the source device may selectand transmit a command supported in not the old protocol but the newprotocol.

If it is determined that the AV receiver supports the new protocol, atoperation S940 the source device generates a content signal having avideo format corresponding to the new protocol within a range of theEDID and transmits it to the AV receiver. If 4K UHD is a video formathaving the highest quality and resolution among various video formatsdesigned in the EDID, the source device selects the 4K UHD video format.

On the other hand, if it is determined that the AV receiver supports notthe new protocol but only the old protocol, at operation S950 the sourcedevice generates a content signal having a video format corresponding tothe old protocol without referring to the EDID, and transmits thegenerated content signal to the AV receiver. For example, even if the 4kUHD is a video format having the highest quality and the highestresolution among various video formats designated in the EDID, thesource device may select a video format having the highest quality of1080p among the video formats supported in the old protocol regardlessof the EDID.

In the foregoing example embodiments, the source device uses the methodof acquiring information by accessing the address of the AV receiverdesignated in specific standards or making a request for a reply to acommand by sending the command based on the standards to the AVreceiver, thereby determining whether the AV receiver supports thestandards.

However, there are no limits to the method of determining what standardsthe AV receiver supports. For example, the AV receiver may also have theEDID. In this case, the source device acquires and analyzes the EDID ofthe AV receiver in order to determine what standards the AV receiverSupports. Below, an example embodiment related to this will bedescribed.

FIG. 23 is a block diagram illustrating an example principle in which asource device 870 determines support standards supported in an AVreceiver 880 in a system according to a ninth example embodiment.

As illustrated in FIG. 23, the system according to the ninth exampleembodiment includes a source device 870, an AV receiver 880 and a sinkdevice 890. The AV receiver 880 has an input terminal for connectionwith the source device 870, and an output terminal for connection withthe sink device 890.

The sink device 890 stores its own EDID, which, in this example isreferred to as EDID-B 891. Further, the AV receiver 880 stores its ownEDID, which, in this example, is referred to as EDID-A 881.

First, the AV receiver 880 copies and stores the EDID-B 891 from thesink device 890. The AV receiver 880 is storing its own EDID, e.g., theEDID-A 881, and the EDID of the sink device 890, e.g., the EDID-B 891copied from the sink device 890.

Next, the source device 870 accesses the AV receiver 880 and acquiresthe EDID-A 881 and EDID-B 891 stored in the AV receiver 880. There aremany methods of determining that the EDID-A 881 is related to the AVreceiver 880 and the EDID-B 891 is related to the sink device 890. Forexample, the EDID generally records a name, a model number, etc. of adevice, and therefore the source device 870 can determines which EDID isrelated to which device by analyzing the EDID-A 881 and the EDID-B 891.Alternatively, the AV receiver 880 may store the EDID-A 881 and theEDID-B 891 in previously designated addresses, and the source device 870may determine which EDID is related to which device when the sourcedevice 870 acquires the EDID-A 881 and EDID-B 891 from the respectiveaddresses.

The source device 870 analyzes the EDID-B 891 to determine a videoformat supported in the sink device 890. Further, the source device 870analyzes the EDID-A 881 to determine versions of multimedia interfacestandards, content transfer security standards, etc. supported in the AVreceiver 880.

Thus, the source device 870 determines the standards supported in the AVreceiver 880.

FIG. 24 is a flowchart illustrating an example source device accordingto the ninth example embodiment providing a content signal to a sinkdevice through the AV receiver.

As illustrated in FIG. 24, at operation S1110 the source device detectsconnections with the AV receiver and the sink device.

At operation S1120 the source device acquires first EDID of the AVreceiver and second EDID of sink device from the AV receiver.

At operation S1130 the source device determines a first video formathaving the highest level supportable in the sink device based on thesecond EDID of the sink device.

At operation S1140 the source device determines the standardssupportable in the AV receiver based on the first EDID of the AVreceiver.

At operation S1150 the source device determines whether the standardssupportable in the AV receiver can support the first video format.

If the standards of the AV receiver can support the first video format,at operation S1160 the source device generates a content signal inaccordance with the first video format and transmits the generatedcontent signal to the AV receiver.

On the other hand, if the standards of the AV receiver cannot supportthe first video format, at operation S1170 the source device generates acontent signal in accordance with the second video format supportable inthe AV receiver among video formats inferior to the first video formatand transmits the generated content signal to the AV receiver.

In the foregoing example embodiments, the source device controls mainoperations, and this may be effective when the system employs theexisting AV receiver. However, the present disclosure is not limited tothe foregoing example embodiments. Alternatively, the AV receiver may beconfigured to modify the EDID of the sink device and control the mainoperations instead of the source device. Below, an example embodimentrelated to this will be described.

FIG. 25 is a block diagram illustrating an example principle in which anAV receiver 920 processes EDID of a sink device 930 in a systemaccording to a tenth example embodiment;

As illustrated in FIG. 25, the system according to the tenth exampleembodiment includes a source device 910, an AV receiver 920 and a sinkdevice 930. The source device 910 is connected to an input terminal ofthe AV receiver 920, and the sink device 930 is connected to an outputterminal of the AV receiver 920.

The AV receiver 920 accesses the sink device 930 and acquires and storesEDID of the sink device 930, e.g., EDID-C 931. The AV receiver 920analyzes an item of “supportable video mode” where video formatssupportable by the sink device 930 are designated in the EDID-C 931.

The AV receiver 920 determines whether there is a video format notsupportable by the AV receiver 920 among the video formats designated inthe supportable video mode of the EDID-C 931. If all the video formatsare processible in the AV receiver 920, the AV receiver 920 does notmodify, but maintains the EDID-C 931.

On the other hand, if there is a video format not processible in the AVreceiver 920, the AV receiver 920 deletes the corresponding video formatand thus modifies the EDID-C 931 into EDID-D 932. Thus, the videoformats designated in the supportable video mode of the EDID-D 932 areall processible by the AV receiver 920.

The source device 910 accesses the AV receiver 920 and acquires the EDIDof the sink device 930, e.g., one of the EDID-C 931 and the EDID-D 932.The source device 910 transmits a content signal corresponding to avideo format designated in the acquired EDID to the AV receiver withoutany additional operation.

FIG. 26 is a diagram illustrating an example in which the AV receiver920 modifies the EDID of the sink device 930 in the system according tothe tenth example embodiment.

As illustrated in FIG. 26, the AV receiver acquires the EDID of the sinkdevice, e.g., the EDID-C 931 from the sink device.

The AV receiver analyzes the item of the supportable video mode, wherethe video formats supportable by the sink device are designated, amongmany items of the EDID-C 931.

The supportable video mode of the EDID-C 931 may for example includeresolutions of 2160p, 1080p and 576p for an image. Based on thisanalysis, the AV receiver determines that the resolution of 2160p, e.g.,a 4k UHD image is the highest quality of the video format displayable inthe sink device, and also determines that the sink device is capable ofdisplaying an image having the resolution of 1080p or 576p.

The AV receiver determines whether there is a video format notprocessible by itself among the video formats designated in thesupportable video mode of the EDID-C 931. For example, the AV receiverdetermines whether it can process the video format having the highestresolution of 2160p designated in the EDID-C 931, and maintains theEDID-C 931 without modification if it can process the video format of2160p.

On the other hand, if it is determined that there is a video format notprocessible by the AV receiver among the video formats designated in thesupportable video mode of the EDID-C 931, the AV receiver deletes thecorresponding video format from the EDID-C 931 and thus modifies theEDID-C 931 into the EDID-D 932. For example, if the AV receiver 920cannot process the video format having the resolution of 2160p but canprocess the video format having the resolution of 1080p or 576p, the AVreceiver deletes the video format of 2160p among the video formats inthe EDID-C 931 but maintains the video formats of 1080p and 576p.

Otherwise, the AV receiver does not modify the EDID-C 931 and does notsupport the SCDC or HDCP 2.2 as a condition of whether to support 4K,thereby guiding the source device not to process the video format havingthe resolution of 2160p.

Thus, the source device will acquire the EDID-D 932 from the AV receiverin the future. Accordingly, the source device sends the AV receiver acontent signal corresponding to the video format of 1080p processible bythe AV receiver instead of the video format of 2160p not processible bythe AV receiver.

FIG. 27 is a flowchart illustrating an example AV receiver according tothe tenth example embodiment modifying the EDID and sending the modifiedEDID to the source device.

As illustrated in FIG. 27, at operation S1210 the AV receiver acquiresthe EDID from the sink device.

At operation S1220 the AV receiver analyzes video formats designated inthe acquired EDID.

At operation S1230 the AV receiver determines whether there is a videoformat not supportable by itself among the analyzed video formats.

If it is determined that there is a video format not supportable by theAV receiver among the analyzed video formats, at operation S1240 the AVreceiver modifies the EDID to delete the video format not supportable bythe AV receiver EDID.

On the other hand, if it is determined that all the analyzed videoformats are supportable by the AV receiver, at operation S1250 the AVreceiver does not modify but maintain the EDID.

At operation S1260 the AV receiver stores the EDID therein to beacquired by the source device.

Thus, the AV receiver prevents and/or avoids a content signal notprocessible by itself from being received from the source device.

The methods according to the foregoing example embodiments may beachieved in the form of a program command that can be implemented invarious computers, and recorded in a computer readable medium. Such acomputer readable medium may include a program command, a data file, adata structure or the like, or combination thereof. For example, thecomputer readable medium may be stored in a voltage or nonvolatilestorage such as a read only memory (ROM) or the like, regardless ofwhether it is deletable or rewritable, for example, a RAM, a memorychip, a device or integrated circuit (IC) like memory, or an opticallyor magnetically recordable or machine (e.g., a computer)-readablestorage medium, for example, a compact disk (CD), a digital versatiledisk (DVD), a magnetic disk, a magnetic tape or the like. It will beappreciated that a memory, which can be included in a mobile terminal,is an example of the machine-readable storage medium suitable forstoring a program having instructions for realizing the exampleembodiments. The program command recorded in this storage medium may bespecially designed and configured according to the example embodiments,or may be publicly known and available to those skilled in the art ofcomputer software.

Although various embodiments have been illustrated and described, itwill be appreciated by those skilled in the art that changes may be madein these example embodiments without departing from the principles andspirit of the disclosure, the scope of which is defined in the appendedclaims and their equivalents.

1-19. (canceled)
 20. A video content providing apparatus comprising: anoutput portion comprising output circuitry configured to transmit acontent signal to a relay connected to an image processing apparatusincluding image processing circuitry to provide the content signal to animage processing apparatus; and at least one processor configured to:receive, from the relay, formation information supported by the imageprocessing apparatus, and if it is determined that the relay does notsupport a first format, output the content signal corresponding to asecond format different from the first format and supportable by therelay.
 21. The video content providing apparatus according to claim 20,wherein the first format and the second format are different in imagequality from one another.
 22. The video content providing apparatusaccording to claim 21, wherein the image quality depends on at least oneor more of a resolution and frames per second.
 23. The video contentproviding apparatus according to claim 20, wherein the at least oneprocessor is configured to determine that the relay supports the firstformat if the relay supports preset first-version interface standard.24. The video content providing apparatus according to claim 23, whereinthe at least one processor is configured to transmit a command based onthe first-version interface standard to the relay, and to determine thatthe relay supports the first-version interface standard if a reply tothe command is received from the relay within a predetermined period oftime, and to determine that the relay does not support the first-versioninterface standard if a reply to the command is not received from therelay within the predetermined period of time.
 25. The video contentproviding apparatus according to claim 23, wherein the at least oneprocessor is configured to access a preset address designated in thefirst-version interface standard of the relay to determine whether datadesignated corresponding to the address is acquirable, and to determinethat the relay supports the first-version interface standard if the datais acquirable, and to determine that the relay does not support thefirst-version interface standard if the data is not acquirable.
 26. Thevideo content providing apparatus according to claim 23, wherein thefirst version interface standard comprises high definition multimediainterface (HDMI) 2.0.
 27. The video content providing apparatusaccording to claim 26, wherein the at least one processor is configuredto determine that the relay supports HDMI 2.0 if the relay can performcommunication using a status and control data channel (SCDC), and todetermine that the relay does not support HDMI 2.0 if the relay cannotperform communication using the SCDC.
 28. The video content providingapparatus according to claim 23, wherein the first-version interfacestandard comprises high-bandwidth digital content protection (HDCP) 2.2.29. The video content providing apparatus according to claim 23 whereinthe at least one processor is configured to communicate with the relaythrough a cable for connecting the output portion and the relay.
 30. Thevideo content providing apparatus according to claim 23, wherein theoutput circuitry of the output portion is configured to wirelesslycommunicate with the relay, and the processor is configured towirelessly communicate with the relay through the output circuitry. 31.The video content providing apparatus according to claim 20, wherein theformation information comprises extended display identification data(EDID) received from the image processing apparatus and stored in therelay, and the at least one processor is configured to acquire the EDIDfrom the relay.
 32. The video content providing apparatus according toclaim 20, wherein the at least one processor is configured to output thecontent signal corresponding to the first format if it is determinedthat the relay supports the first format.
 33. A method of controlling avideo content providing apparatus comprising: receiving, from the relay,formation information supported by an image processing apparatuscomprising image processing circuitry; determining whether the relaysupports a first format; and outputting a content signal correspondingto a second format different from the first format and supportable bythe relay, if it is determined that the relay does not support the firstformat.
 34. A system comprising: a video content providing apparatusconfigured to provide a content signal; an image processing apparatusconfigured to display an image based on the content signal; and a relayconfigured to relay the content signal from the video content providingapparatus to the image processing apparatus, wherein the video contentproviding apparatus comprises: an output portion comprising outputcircuitry configured to transmit the content signal to the relay; atleast one processor configured to: receive, from the relay, formationinformation supported by the image processing apparatus, and if it isdetermined that the relay does not support a first format, output thecontent signal corresponding to a second format different from the firstformat and supportable by the relay.
 35. The system according to claim34, wherein the at least one processor is configured to output thecontent signal corresponding to the first format when it is determinedthat the relay supports the first format.
 36. The system according toclaim 34, wherein the relay is configured to store the formationinformation received from the image processing apparatus, and totransmit the stored formation information to the video content providingapparatus.